Antoine Soulier via ffmpeg-devel: > A file format is described in Bluetooth SIG LC3 and ETSI TS 103 634, for > test purpose. This is the format implemented here. > > Signed-off-by: Antoine Soulier <asoul...@google.com> > --- > Changelog | 1 + > doc/muxers.texi | 6 ++ > libavformat/Makefile | 2 + > libavformat/allformats.c | 2 + > libavformat/lc3dec.c | 135 +++++++++++++++++++++++++++++++++++++++ > libavformat/lc3enc.c | 102 +++++++++++++++++++++++++++++ > 6 files changed, 248 insertions(+) > create mode 100644 libavformat/lc3dec.c > create mode 100644 libavformat/lc3enc.c > > diff --git a/Changelog b/Changelog > index 83a4cf7888..08c200a41d 100644 > --- a/Changelog > +++ b/Changelog > @@ -2,6 +2,7 @@ Entries are sorted chronologically from oldest to youngest > within each release, > releases are sorted from youngest to oldest. > > version <next>: > +- LC3/LC3plus demuxer and muxer > - LC3/LC3plus decoding/encoding using external library liblc3 > > > diff --git a/doc/muxers.texi b/doc/muxers.texi > index a10a8e216f..9687746c30 100644 > --- a/doc/muxers.texi > +++ b/doc/muxers.texi > @@ -2612,6 +2612,12 @@ WebDAV server every second: > ffmpeg -f x11grab -framerate 1 -i :0.0 -q:v 6 -update 1 -protocol_opts > method=PUT http://example.com/desktop.jpg > @end example > > +@section lc3 > +Bluetooth SIG Low Complexity Communication Codec audio (LC3), or > +ETSI TS 103 634 Low Complexity Communication Codec plus (LC3plus). > + > +This muxer accepts a single @code{lc3} audio stream. > + > @section matroska > > Matroska container muxer. > diff --git a/libavformat/Makefile b/libavformat/Makefile > index 44aa485029..4961c42852 100644 > --- a/libavformat/Makefile > +++ b/libavformat/Makefile > @@ -332,6 +332,8 @@ OBJS-$(CONFIG_KVAG_DEMUXER) += kvag.o > OBJS-$(CONFIG_KVAG_MUXER) += kvag.o rawenc.o > OBJS-$(CONFIG_LAF_DEMUXER) += lafdec.o > OBJS-$(CONFIG_LATM_MUXER) += latmenc.o rawenc.o > +OBJS-$(CONFIG_LC3_DEMUXER) += lc3dec.o > +OBJS-$(CONFIG_LC3_MUXER) += lc3enc.o > OBJS-$(CONFIG_LMLM4_DEMUXER) += lmlm4.o > OBJS-$(CONFIG_LOAS_DEMUXER) += loasdec.o rawdec.o > OBJS-$(CONFIG_LUODAT_DEMUXER) += luodatdec.o > diff --git a/libavformat/allformats.c b/libavformat/allformats.c > index 9df42bb87a..0b36a7c3eb 100644 > --- a/libavformat/allformats.c > +++ b/libavformat/allformats.c > @@ -252,6 +252,8 @@ extern const FFInputFormat ff_kvag_demuxer; > extern const FFOutputFormat ff_kvag_muxer; > extern const FFInputFormat ff_laf_demuxer; > extern const FFOutputFormat ff_latm_muxer; > +extern const FFInputFormat ff_lc3_demuxer; > +extern const FFOutputFormat ff_lc3_muxer; > extern const FFInputFormat ff_lmlm4_demuxer; > extern const FFInputFormat ff_loas_demuxer; > extern const FFInputFormat ff_luodat_demuxer; > diff --git a/libavformat/lc3dec.c b/libavformat/lc3dec.c > new file mode 100644 > index 0000000000..9ca9825f1b > --- /dev/null > +++ b/libavformat/lc3dec.c > @@ -0,0 +1,135 @@ > +/* > + * LC3 demuxer > + * Copyright (C) 2024 Antoine Soulier <asoul...@google.com> > + * > + * This file is part of FFmpeg. > + * > + * FFmpeg is free software; you can redistribute it and/or > + * modify it under the terms of the GNU Lesser General Public > + * License as published by the Free Software Foundation; either > + * version 2.1 of the License, or (at your option) any later version. > + * > + * FFmpeg is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + * > + * You should have received a copy of the GNU Lesser General Public > + * License along with FFmpeg; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 > USA > + */ > + > +/** > + * @file > + * Based on the file format specified by : > + * > + * - Bluetooth SIG - Low Complexity Communication Codec Test Suite > + * https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=502301 > + * 3.2.8.2 Reference LC3 Codec Bitstream Format > + * > + * - ETSI TI 103 634 V1.4.1 - Low Complexity Communication Codec plus > + * > https://www.etsi.org/deliver/etsi_ts/103600_103699/103634/01.04.01_60/ts_103634v010401p.pdf > + * LC3plus conformance script package > + */ > + > +#include "libavcodec/packet.h" > +#include "libavutil/intreadwrite.h" > + > +#include "avformat.h" > +#include "avio.h" > +#include "demux.h" > +#include "internal.h" > + > +typedef struct LC3DemuxContext { > + int frame_samples; > + int64_t position; > + int64_t length; > +} LC3DemuxContext; > + > +static int lc3_read_header(AVFormatContext *s) > +{ > + LC3DemuxContext *lc3 = s->priv_data; > + AVStream *st = NULL; > + uint16_t tag, hdr_size; > + uint16_t frame_us; > + uint32_t length; > + int ep_mode, hr_mode; > + int srate_hz, channels, bit_rate; > + int num_extra_params, ret; > + > + tag = avio_rb16(s->pb); > + hdr_size = avio_rl16(s->pb); > + > + if (tag != 0x1ccc || hdr_size < 9 * sizeof(uint16_t)) > + return AVERROR_INVALIDDATA; > + > + num_extra_params = hdr_size / sizeof(uint16_t) - 9; > + > + srate_hz = avio_rl16(s->pb) * 100; > + bit_rate = avio_rl16(s->pb) * 100; > + channels = avio_rl16(s->pb); > + frame_us = avio_rl16(s->pb) * 10;
There is nothing that guarantees that the RHS will fit into an uint16_t. Is there a reason why you are using a more precise timebase for the extradata than the container format? > + ep_mode = avio_rl16(s->pb) != 0; > + length = avio_rl32(s->pb); > + hr_mode = num_extra_params >= 1 && avio_rl16(s->pb); > + > + st = avformat_new_stream(s, NULL); > + if (!st) > + return AVERROR(ENOMEM); > + > + avpriv_set_pts_info(st, 32, 1, srate_hz); Why 32? This format provides no timestamps, so it makes no sense for them to be wrapped. > + st->duration = length; > + > + st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO; > + st->codecpar->codec_id = AV_CODEC_ID_LC3; > + st->codecpar->sample_rate = srate_hz; > + st->codecpar->bit_rate = bit_rate; > + st->codecpar->ch_layout.nb_channels = channels; > + > + if ((ret = ff_alloc_extradata(st->codecpar, 6)) < 0) { > + av_log(s, AV_LOG_ERROR, "Could not allocate extradata\n"); Pointless logmessage > + return ret; > + } > + > + AV_WL16(st->codecpar->extradata + 0, frame_us); > + AV_WL16(st->codecpar->extradata + 2, ep_mode); > + AV_WL16(st->codecpar->extradata + 4, hr_mode); > + > + lc3->frame_samples = av_rescale(frame_us, srate_hz, 1000*1000); > + > + lc3->position = 0; > + lc3->length = st->duration + > + av_rescale(frame_us == 7500 ? 4000 : 2500, srate_hz, 1000*1000); > + > + return 0; > +} > + > +static int lc3_read_packet(AVFormatContext *s, AVPacket *pkt) > +{ > + LC3DemuxContext *lc3 = s->priv_data; > + AVIOContext *pb = s->pb; > + int ret; > + > + ret = av_get_packet(s->pb, pkt, avio_rl16(pb)); > + if (ret < 0) > + return ret; > + > + pkt->duration = lc3->frame_samples; > + lc3->position += lc3->frame_samples; > + if (lc3->position > lc3->length) { > + pkt->duration -= lc3->position - lc3->length; > + lc3->position = lc3->length; > + } > + > + return 0; > +} > + > +const FFInputFormat ff_lc3_demuxer = { > + .p.name = "lc3", > + .p.long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity > Communication Codec)"), > + .p.extensions = "lc3", > + .p.flags = AVFMT_NOBINSEARCH | AVFMT_NOGENSEARCH | > AVFMT_NO_BYTE_SEEK | AVFMT_NOTIMESTAMPS, > + .priv_data_size = sizeof(LC3DemuxContext), > + .read_header = lc3_read_header, > + .read_packet = lc3_read_packet, > +}; > diff --git a/libavformat/lc3enc.c b/libavformat/lc3enc.c > new file mode 100644 > index 0000000000..a7e3e3f4f7 > --- /dev/null > +++ b/libavformat/lc3enc.c > @@ -0,0 +1,102 @@ > +/* > + * LC3 muxer > + * Copyright (C) 2024 Antoine Soulier <asoul...@google.com> > + * > + * This file is part of FFmpeg. > + * > + * FFmpeg is free software; you can redistribute it and/or > + * modify it under the terms of the GNU Lesser General Public > + * License as published by the Free Software Foundation; either > + * version 2.1 of the License, or (at your option) any later version. > + * > + * FFmpeg is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU > + * Lesser General Public License for more details. > + * > + * You should have received a copy of the GNU Lesser General Public > + * License along with FFmpeg; if not, write to the Free Software > + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 > USA > + */ > + > +/** > + * @file > + * Based on the file format specified by : > + * > + * - Bluetooth SIG - Low Complexity Communication Codec Test Suite > + * https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=502301 > + * 3.2.8.2 Reference LC3 Codec Bitstream Format > + * > + * - ETSI TI 103 634 V1.4.1 - Low Complexity Communication Codec plus > + * > https://www.etsi.org/deliver/etsi_ts/103600_103699/103634/01.04.01_60/ts_103634v010401p.pdf > + * LC3plus conformance script package > + */ > + > +#include "libavutil/intreadwrite.h" > + > +#include "avformat.h" > +#include "avio.h" > +#include "mux.h" > +#include "internal.h" > + > +static av_cold int lc3_init(AVFormatContext *s) > +{ > + if (s->nb_streams != 1) { > + av_log(s, AV_LOG_ERROR, "This muxer only supports a single > stream.\n"); > + return AVERROR(EINVAL); > + } > + > + return 0; > +} > + > +static int lc3_write_header(AVFormatContext *s) > +{ > + AVStream *st = s->streams[0]; > + int channels = st->codecpar->ch_layout.nb_channels; > + int srate_hz = st->codecpar->sample_rate; > + int bit_rate = st->codecpar->bit_rate; > + uint16_t frame_us = 10000; > + int ep_mode = 0, hr_mode = 0; > + uint32_t nb_samples = av_rescale_q( > + st->duration, st->time_base, (AVRational){ 1, srate_hz }); > + > + if (st->codecpar->extradata_size >= 2) > + frame_us = AV_RL16(st->codecpar->extradata + 0); > + > + if (st->codecpar->extradata_size >= 6) { > + ep_mode = AV_RL16(st->codecpar->extradata + 2); > + hr_mode = AV_RL16(st->codecpar->extradata + 4); > + } Given that this is not an established format, we can simply demand that extradata_size has to be >= 6. > + > + avio_wb16(s->pb, 0x1ccc); > + avio_wl16(s->pb, (9 + hr_mode) * sizeof(uint16_t)); > + avio_wl16(s->pb, srate_hz / 100); > + avio_wl16(s->pb, bit_rate / 100); > + avio_wl16(s->pb, channels); > + avio_wl16(s->pb, frame_us / 10); > + avio_wl16(s->pb, ep_mode); > + avio_wl32(s->pb, nb_samples); > + if (hr_mode) > + avio_wl16(s->pb, hr_mode); > + > + return 0; > +} > + > +static int lc3_write_packet(AVFormatContext *s, AVPacket *pkt) > +{ > + avio_wl16(s->pb, pkt->size); > + avio_write(s->pb, pkt->data, pkt->size); > + return 0; > +} > + > +const FFOutputFormat ff_lc3_muxer = { > + .p.name = "lc3", > + .p.long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity Communication > Codec)"), > + .p.extensions = "lc3", > + .p.audio_codec = AV_CODEC_ID_LC3, > + .p.video_codec = AV_CODEC_ID_NONE, > + .p.flags = AVFMT_NOTIMESTAMPS, > + .init = lc3_init, > + .write_header = lc3_write_header, > + .write_packet = lc3_write_packet, > +}; _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".